This invention relates a medical material having excellent puncture resistance and biocompatibility which is adapted for use at a site of repeated puncture with a medical needle. More specifically, this invention relates to a puncture resistant, biocompatible tubular structure such as an artificial medical material.
Some medical materials are repeatedly punctured by a medical needle, and kept in contact with a body tissue. A sheet of polyurethane or silicone rubber; a knitted or woven fabric or a felt of Dacron.RTM.; a stretched sheet or a felt of Teflon.RTM.; and the like have been used for such medical materials.
Such medical materials, however, suffered from insufficient puncture resistance as well as biocompatibility, and as a consequence, various unfavorable problems occurred by the use of such medical material at a site where the material was kept in a prolonged contact with a body tissue.
In hemodialysis, an interior shunt is usually formed by anastomosing an artery with a vein. Such a shunt, however, can not be formed when the patient has a damaged artery or vein. In such case, an artificial blood vessel prepared from Teflon.RTM. has been implanted at the corresponding site. Such an artificial blood vessel, however, suffered from various problems after prolonged use and repeated puncture with a medical needle. The insufficient puncture resistance of such an artificial blood vessel resulted in blood leakage upon anastomosis and after repeated puncture with the medical needle, and such blood leakage resulted in bacterial infection, formation of ulcer, chronic inflammation, formation or bump and hematoma, calcification, and the like. The conventional artificial blood vessel also suffered from difference in physical properties with the host blood vessel to which it is anastomosed, and such difference often resulted in the thickening of the blood vessel at the site of the anastomosis.